The consumption of fresh fruits and vegetables is a critical portion of a balanced diet. However, due to the potential for contamination by pathogens, consumption of raw or minimally processed fresh fruit and vegetables may pose a real danger to consumers, especially young children or others having a weakened immune system. Therefore, the development of further processing techniques to reduce the risk of consuming contaminate fruits and vegetables is paramount to the increased consumption of fresh fruits and vegetables by people of all ages.
Furthermore, fresh fruit and vegetables can easily be subject to spoilage, particularly when the fruits and vegetables are not stored in a cold environment, such as a refrigerator, but kept at room temperature.
Modified atmosphere packaging (MAP) and controlled storage (CA) are often used to alter the gaseous environment of a stored fruit or vegetable resulting in an extension of shelf life due to their effectiveness of destroying food pathogens. These techniques modify the atmosphere surrounding the fruit and vegetables by changing the ratio of oxygen and carbon dioxide resulting in the alteration or disruption of the cell membranes of the microorganisms, such as pathogens. The drawback to the extensive use and application of MAP and CA is that while they may destroy certain microorganisms, and therefor inhibit spoilage, they would allow such pathogens such as Clostridium perfringens, Clostridium botulinum and Lysteria monocytogenes to still survive, thereby resulting in a false sense of security to unsuspecting consumers.
Various substances, such as ozone or singlet oxygen has been shown to have similar antimicrobial effects to that of MAP, CA as well as common chemical disinfectants, such as chlorine and chlorine dioxide. Ozone may be an effective alternative to sanitizers for fruits and vegetables since that it acts as a progressive oxidizer of cellular components, such as polyunsaturated fatty acids, amino acids and protein. The degradation of the cellular envelope of a microorganism results in destruction and leakage of cell components, and subsequent deaths of several of types of food-borne pathogens. Excessive application of ozone, however, may result in surface discoloration of fruits and vegetables such as peaches, carrots and broccoli florets. More recent studies of the application of ozone to table grapes have shown that it is not only effective in controlling post-harvest decay caused by fungi, but was also effective in eliciting an increase in the phytoalexins Reszeratrol and pterostilbnes. These findings on the effectiveness of ozone are significant in that they show the potential of this technique to increase the levels of very powerful antioxidants, both of which have been demonstrated to be effective in reducing several risk factors associated with degenerative diseases such as cancer, cardiovascular diseases, arthritis and other inflammatory diseases.
Substituting fresh fruit for processed fruit is frequently cited to reduce cancer, heart disease and excess weight. The U.S. Department of Agriculture estimated in 2004 that Americans eat only half the fresh fruit that is needed. Despite having gained the knowledge that increasing fresh fruit consumption is beneficial, making this diet change has proven to be difficult for most people. This is in part caused by the higher cost of fresh fruit and vegetables relative to heavily processed food, so that people are inclined to purchase less fruit and vegetables and eat them sparingly. The shelf life for fresh fruits and vegetables is substantially shorter than that of processed foods. It is estimated that between 20% and 30% of all food spoils before it is consumed. Additionally, over-ripened fruit often serves as a breeding ground for fruit flies. These fruit flies are hard to eliminate without removing all fruit from the home for several days, thereby annoying consumers.
Many consumers turn to refrigeration in order to extend the life of their fruit and vegetables. Unfortunately, refrigeration takes the fruit out of sight so consumers tend to forget about it, and fail to eat it, and thereby lose the benefits of eating fruit. An additional drawback to refrigeration is that when many fruits are eaten cold, they lose a significant amount of taste as well as their appeal.
Several U.S. patents have issued which are directed to various systems for increasing the shelf life of food, using ozone or a similar substance. For example, U.S. Pat. No. 1,215,254, to Darden describes a device for preserving organic substances, such as fruit, vegetables, meats and the like. These materials would be provided within containers or cells having an ozonizer equipped to charge the air within the containers or cells with as much as 5% ozone. However, it is noted that the system described in the Darden patent is used in conjunction with a cold container or cell and would not be easily converted to a product used in an individual's home.
U.S. Pat. No. 6,485,769, issued to Audi et al describes a method and apparatus for decreasing the bacteria count of a food commodity by subjecting the food commodity contained in a sealed container with ozone produced from an ozone generator. A fluid stream generated by the ozone generator would include approximately 1% to 20% of ozone when oxygen or air is fed to the ozone generator. It is noted that this patent does not specifically indicate that the food included in the sealed container would be fruit. More importantly, as indicated in the Field of the Invention, the patent to Audi et al is directed to a method for reducing pathogenic microorganism population on food commodities during food processing, and not after the food has been delivered to a person's home.
Similarly, U.S. Pat. No. 6,162,477, issued to Crisinel et al discusses a process and apparatus for treating food products prior to the food products being introduced to the individual's home. An oxygen-containing gas mixture would feed an ozonizer utilized to contact the food product for the purpose of sanitizing and deodorizing the food product.
U.S. Pat. No. 6,200,618, issued to Smith et al describes a method for reducing the microbial population of a food in a container. An ozone injector is used to inject ozone, along with water to an application zone in which the food is provided. The ozonated wash liquid is used to contact the food for a period of time preferably between 5 to 15 minutes, thereby disinfecting the surface of the food. However, as previously indicated, water must be injected into the container along with the ozone, thereby making it more difficult to use in a home environment.